Groundwater contamination by chlorinated compounds is a significant risk to public health. Chlorine-containing compounds-ranging from pesticides to industrial solvents-are slow to degrade through natural pathways. Their wide-ranging presence is notable; for example, the industrial solvent trichloroethylene (TCE) has been detected at over fourteen-hundred DOD installations, twenty-three DOE installations, and thousands of commercial and residential sites nationwide, including 60% of Superfund sites. Although various remediation techniques are under study, all sites would benefit from rapid, ppb-level monitoring. These compounds are widely present at minute, low-part-per-billion (ppb) concentrations. At the same time, our water sources are threatened by numerous other pollutants with regulatory limits at ppb-levels. Currently available laboratory-based tools that ca measure these very low concentrations are expensive, complex, and cumbersome instruments. They do not enable the types of rapid, frequent, economical and broad-based testing needed to adequately monitor the nation's water sources. Next-generation capabilities to test water samples at sub-ppb for a wide-variety of compounds in fewer than five minutes would vastly improve the capabilities of water monitors and researchers. This ability will in turn allow water suppliers to increase monitoring frequency and to implement remediation steps, and will allow researchers to focus on obtaining more data and a better understanding of the health effects of chronic exposure. OndaVia intends to develop the advanced technology that is needed. For the multi-phase SBIR project envisioned here, OndaVia proposes to develop, prototype, validate, and commercialize a rapid- analysis instrument designed to measure compounds in aqueous solution using surface-enhanced Raman spectroscopy (SERS). This instrument relies upon OndaVia's proven and proprietary SERS detection technology that is both sensitive and quantitative, resulting in an easy-to-use, rapid-analysis instrument with few-parts-per-billion sensitivity. Specific Phase I Aims are focused on proving the feasibility of 1) detecting TCE at 5-ppb using our unique detector, and 2) determining a quantitative calibration curve for TCE over 0- to 100-ppb. Phase I success will set the stage for follow-on Phase II work focused on fully demonstrating/validating the capabilities of our prototype system with the goal of achieving 5-ppb detection levels in field samples in preparation for Phase III commercial development with private- sector investors/industry partners.